Conventional shifting mechanisms, through which shifting motions were accomplished through electric motors, were provided, so that an electric motor was provided for generating selection motions, and an electric motor was provided for generating shifting motions. Meanwhile, however, also transmission shifting mechanisms are known, which only have one, or exactly one, electric motor, through whose drive motions, actuating motions for selecting and also actuating motions for shifting gears can be caused. Transmission shifting mechanisms of the latter kind are also called single motor transmission shifting mechanisms, since they only have one or exactly one electric motor.
Embodiments of such single motor transmission shifting mechanisms are disclosed in unpublished U.S. Patent Application Nos. 60/750,538; 60/750,555; 60/750,571; 60/750,572; 60/750,554; 60/750,527; 60/750,526 and 60/750,688 of the applicant, all of which are incorporated herein by reference. Also DE 10 2004 038 955 A1 of the applicant discloses exemplary embodiments of a single motor transmission shifting mechanism.
As can be seen, in particular, also from the state of the art, known single motor transmission shifting mechanism are often, or typically provided, so that they are driven by a threaded spindle.
While in the known embodiments of single motor transmission shifting mechanisms, a threaded spindle is often used to generate a high torque, which is necessary for the shifting motion, the problem of low efficiency (approximately 70%) exists, which is mostly due to the arrangement and connection of the threaded spindle. This requires an electric motor or a servo motor in the known embodiments, which is sized, so that it compensates the torque losses.
From U.S. Patent Application No. 60/750,538 of the applicant, furthermore, a design is known, in which nuts and tubes are being used, wherein coupling ears are provided, to couple them in rotation, while an axial motion is allowed. It has become evident that in some cases these parts are difficult to manufacture and very expensive. With this background, an alternative design for the design is desirable, which is simpler in manufacture.